Hi OP,
How bad was the early morning traffic? If it was heavy, that might explain it. If 33B is bogged down, it would be faster to take 33A and take the 85 north on-ramp and merge at the end of the 33B ramp. Google maps has suggested this to me many times while in ATL rush hour.
For those that never been to Atlanta, essentially, if you're driving on 285 eastbound, even if you took the 85 south exit, there is a path to take you onto 85 north. These looparounds is how spaghetti junction got its name.
FYI: I don't own a model 3 but was browsing for info to do research.